Monhagen Lake Dike
Monhagen Lake Dike is an earth dam located in Orange County, New York, built in 1867. It carries a High hazard potential classification and has a fair condition assessment.
About Monhagen Lake Dike
The primary purpose of Monhagen Lake Dike is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Middletown (local government). It impounds the Monhagen Brook near Middletown.
The dam stands 20 feet tall, creates a reservoir covering 65 acres, has a maximum storage capacity of 858 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1867, the structure is one of the older dams in the region, with over a century and a half of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 04/03/2025.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New York dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | New York |
| County | Orange |
| Nearest City | Middletown |
| River/Stream | Monhagen Brook |
| Coordinates | 41.45972, -74.44889 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Year Completed | 1867 (159 years old) |
Storage & Hydraulics
| NID Storage | 858 acre-ft |
| Max Storage | 858 acre-ft |
| Normal Storage | 635 acre-ft |
| Surface Area | 65 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 799 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF MIDDLETOWN |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 04/03/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NY00070 |
| Federal ID | NY00070 |
| More Info | State Dam Safety Program |